The last recession, when WPP almost collapsed under a crippling debt load, is still too fresh in most shareholders' memories for them to believe that WPP can escape the cycle.
Not that anyone is suggesting WPP is in danger of going bust. Any impending downturn is likely to be much shallower than eight years ago and, besides, WPP's balance sheet is in much better shape today.
Under chief executive Martin Sorrell the company has diversified into public relations and consultancy. Although the core advertising and media planning business produced a 9 per cent increase in revenues - suggesting it is taking market share from its rivals - the real growth came in the other areas which now account for almost half of WPP's turnover.
Trading looks robust. Mr Sorrell expects the overall market to grow by 4-5 per cent in 1999 - only slightly less than this year. Early figures for July show revenues up 16 per cent year on year. Factor in WPP's increased focus on financial services and entertainment and the group should easily meet its target of 14 per cent operating margins by 2000.
Nevertheless, WPP is far from immune to a downturn. The operational gearing which allows profits to rise faster than revenues will work in reverse if advertising dips.
On full-year profit forecasts of pounds 205m the shares trade on a forward multiple of 22. For a cyclical business, high enough.